Yamaha R6 2005 Fork Seal Replacement

Fork seals are replaced when they start leaking. It's important to replace the seals in time, since oil can get on the brake disc. Seals are always replaced in pairs, even if one of them isn't leaking. It's also recommended to replace the dust seals, but if they are in good condition, it's optional.

The seal replacement procedure on a 2005 Yamaha R6 is shown in detail in the video; the key points are below.

1. To replace the seals, the fork leg must be removed.
2. Unscrew the top cap: it's best to break it loose while the fork leg is clamped in the lower triple clamp.
3. You need to compress the spring to expose the locknut, break it loose and unscrew the top cap. This requires making a special tool.
4. Remove the spring and the plastic spacer tube. The spring may be conical, so remember how it was installed. At the same time you can check the spring for wear: the spring length should be within 244–249 mm.
5. Drain the oil. To drain more oil, pump the damper rod.
6. Remove the dust seal and the retaining clip.
7. Pull the inner tube out of the outer tube.
   • If the copper guide bushing is pressed into the outer tube, the inner tube will come out of the outer tube easily, and the seal will have to be pried out with a screwdriver.
   • If the copper guide bushing is fitted on the inner tube, the inner tube will have to be knocked out of the outer tube with sharp movements, and the seal will pop out on its own.
8. When fitting a new seal, stretch an oiled piece of plastic film over the end of the inner tube so as not to damage the inner surface of the seal.
9. The seal is driven into the outer tube with a special tool. You can make the tool yourself from an old seal or a plastic pipe.
10. Oil is poured into the outer tube without the spring and the aluminum rod (in the damper rod). The required amount of oil is checked by the distance from the oil level to the top edge of the outer tube. For this motorcycle it should be 92 mm.
11. Everything is reassembled in reverse order. Before compressing the spring with the special tool, it's best to hook the damper rod, since otherwise it will be hard to pull out without tweezers.
12. Final tightening of the top cap is done with the fork leg clamped in the lower triple clamp.

Note:

1. On conventional forks the seal replacement process is very similar, and you can use this video guide for reference.
2. You can replace the seals without disassembling the fork leg. To do this, unscrew the lower end bolt (12), remove the dust seal and the retaining clip, and knock out the seal. But with this approach you won't be able to fill an exact amount of oil and measure the level. Practice shows that if you drain the oil from both legs for a long time while pumping the damper, and fill the same amount of oil, the fork works normally. However, the amount of oil is crucial, and if you overfill or put different amounts in the two legs, the fork will work incorrectly and the seals will leak sooner!
3. You can't drain all the old oil without disassembling the fork. A lot of oil remains in the damper rod and damper.